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I'm struggling with a question I've been asked.

"Why is double stranded genetic material more 'durable' than single stranded one?"

I know that double stranded genetic material is more stable due to multople strands. The single stranded isn't as stable as the double stranded since it lacks the second strand and therefore the bases are open.

Stable isn't the same as durable, and I've never heard in class that one is more durable than the other one. Did I miss something or is this just a mistake?

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    $\begingroup$ I'm having trouble understanding the question right now, but I do know that single stranded RNAs are more likely to be digested by RNAse enzymes than double stranded RNAs. From an error correction viewpoint, the second strand provides a template for fixing the first strand, so single stranded genomes would be more likely to mutate, or just get cut in 2. $\endgroup$ – user137 Jan 11 '15 at 21:51
  • $\begingroup$ A similar question has been asked in the past: biology.stackexchange.com/questions/23851/… $\endgroup$ – Anne Jan 11 '15 at 22:11
  • $\begingroup$ I don't know what one means by durable. For example it could be a simple question of stability as you mention, or is this in reference to DNA data storage where the double stranded nature can be used to identify or recover areas that are damaged over time. $\endgroup$ – James Jan 11 '15 at 23:02
  • $\begingroup$ I'm having troubles as you. I don't know what is meant. I asked my teacher today, and she said that the sentence is totally correct. She meant it like that. Furthermore, she added that it has nothing to do with stability. I don't find anything valueable in my book, nor in the internet. Any help is appreciated. $\endgroup$ – Zerotime Jan 12 '15 at 14:44
  • $\begingroup$ Do you mean durability against physical stress (shearing etc)? $\endgroup$ – WYSIWYG Jan 12 '15 at 16:33
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I'm interpreting "durability" as the DNA's resistance to physical stress, such as shearing. The Bustamante lab at UC Berkeley does a lot of very cool single-molecule biophysics looking at forces involved in protein-protein interactions and protein-DNA interactions. This Bustamante et al. review paper, Single-molecule studies of DNA mechanics includes a look at the force required to break ssDNA and dsDNA:

Single molecules of dsDNA were broken with a receding water meniscus [26] at forces estimated to be 960 pN (correcting Young’s modulus doubles the published scission force of 480 pN). Short dsDNA molecules pulled with an AFM tip [27] sustained forces over 1700 pN.

pN = picoNewton
AFM = atomic force microscopy

dsDNA is more resistant to stretching/shearing forces because the double helix arrangement is "springy". I recommend giving the paper a read for more info. Very cool stuff.

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